1. Field of the Invention
The invention relates to improvements in snatch blocks with two side plates, one of which is called the swing plate and is pivoted about the sheave bolt between the two side plates. More particularly, the present invention relates to an improvement in the construction of the snatch block hook bolt assembly which supports the trunnion or becket to which a hook or other fitting may be attached.
2. Prior Art
Snatch blocks are typically composed of two spaced apart parallel side plates, one of which is called the swing plate and is pivoted about the sheave pin which is between the two side plates. This construction is generally to provide access to the sheave for stringing rope or cable to the sheave.
In the prior art, the first side plate and the second or swing side plate are normally of about the same configuration. A sheave supporting means for supporting a wire rope or line is supported by and held between the two side plates and is generally located at the top of the snatch block. The sheave support means is typically a sheave pin.
The hook bolt assembly is spaced from the sheave supporting means. The hook bolt is provided between the plates such that a trunnion or becket may be supported and to which a hook or other fitting may be attached.
Typically, when the snatch block is assembled for use, a hole in each side plate""s lower portions are aligned. A spool member is attached to one of the side plates and has a hole through the spool member which is slightly larger than the diameter of the hook bolt which extends through the holes in the two side plates. The periphery of the hole of the spool adjacent the side toward the sheave supporting means is aligned with the periphery of the holes in the side plates. This permits the lower bolt to pass through and support the spool member. A hook with a trunnion or becket is typically supported by the spool.
It is known to provide a spool on the hook bolt such that it is welded to one of the plates and the holes in the two plates for the hook bolt are preferably aligned with the hole of the spool. The hook bolt which extends through the spool member is threaded at one end which extends into the swing plate for mating.
Typically, a hook bolt goes through the hole in the first plate, through the spool and is fastened to a nut positioned in or on the swing plate to hold the swing plate in position. It is known to weld a nut for mating the bolt to the swing plate or to provide threads in the hole of the swing plate for such.
Furthermore, it is known at the butt of the threads of the hook bolt to provide a groove into which a C-spring is placed. When the snatch block is completely made up, this C-spring is positioned inside the swinging side plate. When the bolt or side plate is to be removed or opened so that restringing can occur, the bolt is screwed out of the swinging plate but the C-spring abuts the shoulder of the hole of the fixed plate and prevents the bolt from falling out.
Snatch blocks in general are well known. For a discussion of the prior art and the configurations of typical snatch blocks, see U.S. Pat. No. 2,366,636 issued Jan. 2, 1945 to W. H. McKissick et al., U.S. Pat. No. 2,474,433 issued Jun. 28, 1949 to W. H. McKissick, and U.S. Pat. No. 2,649,282 issued Aug. 18, 1953 to J. E. Fate, Jr. Furthermore, see U.S. Pat. No. 4,614,332 issued Sep. 30, 1986 to Wilson.
The prior art snatch block assemblies which provide a hook bolt assembly as described above sometimes suffer from the problems associated with the fabrication of mating parts in heavy duty application directed to steel and other metal components. Because of the tolerance on the mating parts, it is often difficult to align the nut and spool to the side plates.
Furthermore, it is also commonplace that the prior art nut and spool arrangements require extra time and steps in the assembly and fabrication of components due to the need of exacting tolerances of mating parts. The prior art needs continuous monitoring of tolerances on the mating parts and close attention must be paid to changing the line up pins on the welded fixtures. If such tolerances and changing the line up pins are not adhered to properly, the components must be replaced in order to assemble and fabricate a fully functional snatch block.
Furthermore, in the prior art, at least one of the side plate holes needed a chamfered portion for compressing a retaining C-clip. This required specialized production of the holes as opposed to a simple punch or drilling out a hole in the side plate.
Therefore, there is a need and a desire to provide a new and improved snatch block hook bolt assembly that keeps components in line during assembly and fabrication. Furthermore, there is a need and a desire to reduce scrapping of components while providing a functional snatch block.
The present invention is a new and improved snatch block hook bolt assembly which provides a lip or protuberance to a spool such as but not limited to the side in contact with the first or fixed plate such that the lip or protuberance is accommodated in the alignment hole of the first or fixed plate. It is further contemplated that the retaining nut attached to the second or swing plate may also have a lip or protuberance that is accommodated in the alignment hole of the second or swing plate.
The invention of providing a lip or protuberance on the nut and spool keep all the components of the hook bolt assembly in line during fabrication and assembly and provide for a new and improved snatch block and assembling of same. It is still further provided that a C-ring will now engage into the lip of the nut and keep the lower bolt from backing off because the lip and the threads will be concentric. The C-ring will also catch in the spool due to a stepped feature of the spool. Because the spool will align with the nut, grinding will be eliminated.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in this application to the details of construction and to the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
It is, therefore, an object of the present invention to provide a new and improved snatch block hook bolt assembly that provides a means of aligning components of the hook bolt during fabrication.
It is a further object of the present invention to provide a new and improved snatch block hook bolt assembly which is of a more durable and reliable construction than that of the prior art with such features as concentric alignment of components.
An even further object of the present invention is to provide a new and improved snatch block hook bolt assembly which provides for catching a c-ring of the hook bolt or lower bolt of the hook bolt assembly in the spool and thus eliminate the need for chamfering the holes in the side plates.
Still another object of the present invention is to provide a new and improved snatch block hook bolt assembly which is susceptible of a lower cost of manufacture with regard to both materials and labor, which accordingly is then susceptible of lower prices of sale to the consuming industry, thereby making such economically available to the end user.
Another object of the present invention is to provide a new and improved snatch block hook bolt assembly which provides some of the advantages of the prior art, while simultaneously overcoming the disadvantages normally associated therewith.
Yet another object of the present invention is to provide a new and improved snatch block hook bolt assembly which has a more efficient use of materials and hence reduces reworking and the scrapping of components.
Still yet another object of the present invention is to provide a new and improved snatch block hook bolt assembly with a lip or protuberance on a retaining nut for aligning in the second or swinging plate.
It is a further object of the present invention to provide a new and improved snatch block hook bolt assembly which provides a lip or protuberance on a spool of a hook bolt assembly for aligning in the first or fixed plate.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there is illustrated preferred embodiments of the invention.